Lock and alarm

ABSTRACT

A CHAIN TYPE DOOR LOCK HAVING A BELL AND MEANS RESPONSIVE TO AN ATTEMPT TO FORCE THE LOCK TO SOUND THE BELL AND THUS CREATE AN ALARM SIGNAL, SAID MEANS INCLUDING A RACK AND PINION GEAR, MOTION OF THE RACK ROTATING THE GEAR TO TURN A STRIKER TO STRIKE THE BELL.

Feb. 6, 1913 M. DA Sim/A 3,714,922

LOCK AN D ALARM Filed March 9, 1971 was. IIIGA. FIGS- INVENTOR- M/GUEL DA S/L V/I United States Patent Ofi ice 3,714,922 Fates-steel Feb. 6, 1973 3,714,922 LOCK AND ALARM Miguel da Silva, 29 W. North A"e., Cranford, NJ. 07016 Filed Mar. 9, 1971, Ser. No. 122,347 Int. Cl. G081 15/00 US. Cl. 116-14 3 Claims ABSTRACT OF THE DISCLOSURE A chain type door lock having a bell and means responsive to an attempt to force the lock to sound the bell and thus create an alarm signal, said means including a rack and pinion gear, motion of the rack rotating the gear to turn a striker to strike the bell.

SUMMARY OF THE INVENTION My invention is directed toward a door lock of the type having two sections detachably connectable by a chain, one section being mounted on the door, the other section being mounted on the door frame. In my invention, one section includes means responsive to pressure exerted on the chain when in position as an attempt is made to force the door to sound an alarm.

The means includes a bell, a rotatable striker for striking the bell to sound the alarm, a pinion gear which when rotated rotates the striker, and a reciprocable rack moved by pressure on the chain to rotate the gear.

BRIEF DESCRIPTION OF THE DRAVJINGS DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS f Referring now to FIGS. 1-5, the liollowing parts have the following numbers:

key 1 hell 9 chain 2 bell striker cover 3 bell gear 11 spring 4 bell prongs 12 screws 5 lock cylinder 13 lock cylinder plate 6 cover plate 7 door rack 8 cylinder plug 16 The rack 8 is normally hold in withdrawn position by spring 4 whereby chain 2 is held taut between the (free end of the rack and a removable plug 16 of the lock cyldoor frame 14 inder. The plug can always be released by turning key l in cylinder 13 and reinserted by snap fit therein. Should anyone try to force door 15 open with the chain in place, the pressure on the chain will pull the rack outward, rotating gear 11 to cause the striker arms 10 which are flexible to strike the bell prongs 12 whereby the bell sounds an alarm. As soon as the pressure-is removed on the chain, the spring will pull the rack back to normal position.

While I have described my invention with particular reference to the drawings, such is not to be considered as limiting its actual scope.

Having thus described this new is:

1. A door lock, for use in combination with a door and a door frame, comprising:

a key-operated lock cylinder, including a detachable cylinder plug, mountable on the door or door frame;

a lock mechanism, mountable on either the doororthe door frame, and including a horizontally movable rack, responsive to movement of the door with respect to the door frame to sound an alarm;

a chain, coupled to said rack and said detachable cylinder plug, and disposed therebetween;

spring biasing means, coupled to one end of said rack,

for biasing said rack away from said chain and securing said chain taut between said cylinder plug and said rack, so that when said door is moved with respect to said door frame, a force is exerted on said rack by said chain so that said rack moves toward said chain and an alarm is sounded.

2. The door lock as recited in claim 1, further comprising a gear, coupled to said rack, said gear being rotated by said rack when said rack is moved horizontally along its longitudinal axis by the movement of the door with respect to the door frame.

3. The door lock as recited in claim 2, further comprising a bell, and a bell striker, said bell striker being coupled to said gear so that said striker is rotated in response to horizontal movement of said rack.

4/1958 Denmark 116-160 LOUIS J. CAPOZI, Primary Examiner US. Cl, X.R.

invention, what is asserted as i 

